A study of the annual growth of certain cactus showed that, 81 of them, selected at random in a desert region, grew on the average 50.80 mm with a standart deviation of 4.1 mm. What should be the minimum sample size if the error does not exceed 1.1 with probability 0.90? O A.n= 38 O B. n = 55 O C.n = 35 O D.n = 51

A study of the annual growth of certain cactus showed that, 81 of them, selected at random in a desert region, grew on the average 50.80 mm with a standart deviation of 4.1 mm. What should be the minimum sample size if the error does not exceed 1.1 with probability 0.90? O A.n= 38 O B. n = 55 O C.n = 35 O D.n = 51

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

See similar textbooks

Similar questions

The mean weight of a fire ant worker is 3.11 mg with a standard deviation of .49 mg. Suppose we randomly select 14 different fire ant workers having weights F1, F2, , F14. Let S = F1 + F2 + ...+F14 and let M = S/14. This means S is the sample sum and M is the sample mean of the selected ant weights. (Note: random selection means F1 F14 are independent.). Assume the Fis are normally distributed. j) What is the expected value of M - 3.11 ? k) What is the standard deviation of [(M - 3.11)/49]/srt14
3. The thickness of a road is nommally distribuned with standard deviation 5.8 cm. A random sample of 15 roads were taken If the probability that the sample mean road thickness is at least 10.2 cm is K2, whut is the average thickness of all the roads
Suppose that an airline uses a seat width of 16.7 in. Assume that men have hip breadths that are normally distributed with a mean of 14.2 inches, and a standard deviation of 1in. Find the probability that if an individual man is randomly selected that his hip breadths will be greater than 16.7 in.
The weight of items produced by a machine is normally distributed with a mean of 8 ounces and a standard deviation of 2 ounces.Refer to Exhibit 6-5. What is the random variable in this experiment? a. 8 ounces b. Weight of items produced by a machine c. Normal distribution d. 2 ounces
A study reported that finger rings increase the growth of bacteria on health-care workers’ hands. Research suggests that 31 percent of health-care workers who wear rings have bacteria on one or both hands. Suppose that independent random samples of 100 health-care workers wearing rings is selected. What is the standard deviation of the sampling distribution of the sample proportions of health-care workers having bacteria on one or both hands? A. 100 B. 0.0462 C. 0.69
5) The daily revenue at a university snack bar has records to indicate that the mean daily revenue is $2,400 and standard deviation is $600. A random sample of 81 days was selected. Find the approximate probability that the average revenue for the sample is less than $2,300.
Barron’s reported that the average number of weeks an individual is unemployed is 17.5 weeks. Assume that for the population of all unemployed individuals the population mean length of unemployment is 17.5 weeks and that the population standard deviation is 4 weeks. Suppose you would like to select a random sample of 50 unemployed individuals for a followup study. a. Show the sampling distribution of x̅, the sample mean average for a sample of 50 unemployed individuals. b. What is the probability that a simple random sample of 50 unemployed individuals will provide a sample mean within 1 week of the population mean? c. What is the probability that a simple random sample of 50 unemployed individuals will provide a sample mean within 1/2 week of the population mean
A mean undergraduate cost for tuition , fees , room , and board for four-year institutions was 26,489 for a recent academic year. Suppose that the population standard deviation equals 3, 204 and 36 four year institutions are randomly selected .find the probability that the sample mean cost for these 36 schools is between 24,000 and 26, 000.find the corresponding area for the z values.
Given a Normal Distribution with a population mean test score of 500 and a population standard deviation of 100. A.)For a sample of 81 test takers, calculate the standard error of the mean to 2 decimals. B.)What is the probability a sample of 81 test takers will provide a sample mean test score within 20 points of the population mean?
An independent random sample is selected from an approximately normal population with an unknown standard deviation. Find the p-value for the given sample size and test statistic. a. n = 11, T = 1.91 b. n = 17, T = -3.45 c. n = 26, T = 2.485 d. n = 18, T = 0.5
For a normally distributed population with a mean of u = 70 and a standard deviation of o = 10, what is the probability of obtaining a sample mean greater than M= 67 for a sample of n 64 scores? O a.p=0.9675 O b.p= 0.9918 O c.p= 0.4918 O d.p=0.0082
Assume that the mean length of a toothpick is mu = 6 cm , with a stand deviation of sigma = 0.14 cm . 1. If we were to select one toothpick at random, what is the probability that it is longer than 6.004 cm? 2. if we weee to select a Random sample of 45 tooth picks, what is the probability that the sample mean is longer than 6.004 cm?